Some headers are much heavier than others. For example, draper headers used in the harvesting of cereal grains are typically much wider and heavier than hay headers used in the harvesting and windrowing of hay crops. However, there has heretofore been no way for the same tractor of a self-propelled harvester or the same frame of a pull-type machine to provide effective flotation for headers of substantially different weights. Instead, different tractors or frames having their own flotation systems designed to meet their own particular header weight requirements had to be provided.